This doesn't apply to all cases, but in the example given... why are you using images at all? The button style could easily be created using CSS3 and allow you to sidestep all this inconvenience.
I'm going to be honest and say that as a developer my policy toward Android web users is similar to the one I have for Internet Explorer users. It goes something like, "Eh, they're used to the web looking shitty."<p>This is all barring those specific users and/or cases being called out in my site requirements documentation, of course...